Field of the Invention
The present invention relates to a resin sealing apparatus and a resin sealing method for providing resin sealing for a component to be sealed attached onto a substrate by a sealing resin.
Description of the Background Art
In order to form a molded product, a cavity formed by a space filled with a fluid resin is formed in a mold for resin sealing. A so-called film molding method is widely known, in which a mold surface of a mold is covered with a mold release film and thus a resin molded product molded within a cavity is easily separated from the mold surface (refer to, for example, Japanese Patent Laying-Open No. 08-142109). According to this film molding method, the die surface (mold surface) of the mold including the cavity is covered with the release film (mold release film) that is easily separated from the molding die (mold) and the molding resin (sealing resin). The mold is clamped, and thereby, a lead frame which is a component to be molded is clamped. A melted resin (fluid resin) is pressure-fed from a pot to the cavity and the fluid resin is cured, and thereby, a sealing resin is formed. Therefore, the pressure is required to pressure-feed the fluid resin from the pot to the cavity formed by the space into which the fluid resin is injected.
A planar shape of an inner bottom surface of the cavity used in this film molding method is normally a simple shape including a substantially rectangular shape (including a square shape and the same is applied to the following description) or a substantially circular shape. Therefore, a planar shape of an end surface (upper end surface) of the sealing resin (hereinafter referred to as “end surface planar shape”) is also a simple shape including a substantially rectangular shape or a substantially circular shape. Thus, when resin molding is performed with the mold surface of the resin sealing mold covered with the mold release film, the mold release film allows easy release, from the mold surface, of a sealed substrate (molded product) formed by resin sealing of a component to be sealed.
Recently, in increasing cases, the planar shape (including both the end surface planar shape and a planar shape of a portion where the sealing resin is in close contact with the substrate) of the sealing resin has been neither the substantially rectangular shape nor the substantially circular shape, depending on applications. Throughout the specification, a planar shape that is neither the substantially rectangular shape nor the substantially circular shape will be referred to as “unusual planar shape”. First, there is a case in which the inner bottom surface of the cavity has the unusual planar shape. Secondly, there is a case in which an edge portion (a ridge portion forming a boundary between the mold surface subjected to mold clamping and the cavity) of an opening of the cavity has the unusual planar shape. Thirdly, there is a case in which both the inner bottom surface of the cavity and the edge portion of the opening of the cavity have the unusual planar shape.
In order to sufficiently spread the fluid resin over the entire cavity having the inner bottom surface of the unusual planar shape, high pressure is required when pressure-feeding the resin from the pot to the cavity. First, this may cause deformation, break and the like of a wire used to electrically connect the component to be sealed and the substrate. Secondly, this causes an increase in size of a pressing mechanism and therefore an increase in size of a resin sealing apparatus.